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J. A. WIGL.

. )Z TfT/'ITNESSES INVEJW'OR UNITED STATES PATENT OEEICE.

JOHN A. XVIGAII, OF TYNER, YVES" VIRGINIA, ASSIGIIOR OF ONE-HALF TOTHOMAS M. IVIGAIJ, OF SAME PLACE.

Bemmel-Wenen.

SFECIFICATION forming part of Letters Patent No, 398,361, dated February19, 1889. Application filed October 25, i888l Serial No. 289,131` (Nomodehl To all whom it may concern:

Beit known that I, JOHN A. WIIGAL, a citizen of the United States ofAmerica, residing at Tyner, in the county of Vood and State of IV estVirginia, have invented certain new and useful Improvements inBelt-Tighteners; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to lettersor figures of reference marked thereon, which form a part of thisspeci'cation.

My invention relates to an automaticallyoperating eXpansible pulley orbelt tightener; and it consists in the novel construction andcombination of parts, as will be more fully hereinafter described andclaimed.

The object of my invention is to provide a pulley of the character setforth for the purpose of taking up slack in the belt without adjust-ment by hand, the parts thereof being simple and effective in theirconstruction and operation, and strong and durable. I attain this objectby the construction illustrated in the accompanying drawings,whereinlike letters of reference indicate similar parts in the several views,and in which-- Figure l is a side elevation of n'lyimprovtnl pulleyshown as applied. Fig. 2 is a similar View of the pulley detached,showing one of the coniiections removed. Fig. 3 Ais a detail perspectiveview ot' one of the sections of ille pulley.

A and A indicate the two sections of ihe pulley, each of which indimension is less than half if a true circle. On each side of the centerof each of said sections parallel ribs d are formed, and in the webbetween said ribs, near the curved side of each section, elongated slotso are formed; The central part of each section between the ribs a isalso formed with an inclined semi-elliptical slot, a?, adapted to beengaged by an elliptical cam, B, on the driving-shaftll, driven by saidpulley. The slots u?, when united, form a recess sufficiently large toclose in the said cam B when the sections A and A bear against eachother, as will be more fully hereinafter set forth.

In the spaces inclosed by the ribs a in the sections connectingstrips Care mounted on each side of said sections, and are secured to each otherby rivets or pins c, passing through apertures at their outer ends andthrough the elongated slots a in the sections. By said connecting-stripsC the sections A and A of the pulley are held united.

The belt D is readily placed over the pulley by the contractingconstruction thereof. Then the drive-shaft B revolves, the cam B thereonbears against the walls of the two oppositely-situated cam slots orrecesses a2, respectively, at the upper part of one and the lower partof the other, thus forcing the two sections A and A apart, and taking upthe slack of the belt the said pulley is revolved and transmission ofpower effected. Se long as the belt D is of the desired tension the camB holds to the position just described. As soon, however, as the tensionof the belt is slackened or relaxed through stretching thereof or fromlother causes, the cam will force the sections A and A still fartherapart and compensate for or take up said slack. In the movement of thesections A and A they are guided and held true by the connectingstripsC, upon which they slide, as hereinbefore referred to.

Having thus described my invention, I claiml. The combination,substantially as described, of an automatically-expansible pulley,consisting of two semicircular sections having cam-slots centrallyarranged in their meeting edges and united by sliding connecting-strips,and a shaft provided with a cam constructed to lit said cam-slots.

2. A pulley constructed in two sections having central ribs and camrecesses or slots, in

ctmibination with the coimection-strips, the d rive-shaft, and the camengaging the cam recesses or slots for expainling said sections,snl'istantiall y as descri bed.

3. The combination, substantially as described, of a pulley composed oftwo equal ind open dent section s havin g cen trally-arranged Cani-slotsin their meeting edges, and on each side of said cani-slots ribs formedat right anr In testimony whereof affix mysignature in Io gles t0 Saidmeeting edges, elongated slots alfi presence of. twowitnesses.

ranged parallel with the ribs, Connecting- JOHN A. VIGAL. 5 Stripssented between Suid ribs and united nt their outei.I ends by pinspassing through the Witnesses: elongated slots, a shaft, and a @am fixedon the S. B. \VILLIAMS I N, shaft and shaped to fit the cam-slots in theT. M. VIGAL.

meeting edges of the Sections.

